Addition agent and mineral oil lubricant compositions containing the same



employed as thelubricant.

' tion of so-calledvarnishes and sludges-on engine surfaces is a resultof oxidation effects on the bustion chamber.

" These problems becomev particularly acute when ating conditions areencountered, mineral lubri ticularly' acute becauseof the presence ofwater in themineral oil lubricant and in addition to tered.

the oxidation, and corrosion difficulties encountered in the use ofmineraloil lubricants.

which; are stable instorageand, use and in which oxidation, andcorrosion. efiects'gare n ate i 1 hibited, a

Patented Apr. 22, 1952 UNITED" STATES? PATENT OFFICE ADDITION AGENTANDMINERAL OIL LUBRI- CANT COMPOSITIONSCONTAINING THE -SAME Herschel G..Smith, Wallingford, and Troy L. Cantrell, Lansdowne,,Pag 'assignors. toGulf Oil Corporation, Pittsburgh;

Pennsylvania No Drawing;

ra, a corporation of Application February 4,- 1948, Serial No. 6,344

25 Claims. "(CL 25246.6')

This. invention. relates to addition agents and mineral oillubricantcompositions containing.- the same and, more, particularly, itis concerned with improvement agents which, confer improved anti-foxidant, corrosion-inhibitingand pressure-carry-E 5 ing properties onmineraloil lubricants.

. It is recognized in the art. that mineral oil lubricants are readily.oxidized under service conditionsvthereby reducing the service life ofinternal combustion engines. and steam turbines. A conl0 comitant effectis corrosion of bearing surfaces.

a highly refined paraflinic base, mineralv oil. is

In. the lubrication of internal combustionengines of all types,particularly whensevere opercating oils frequently prove unsatisfactorybecause they tend to deposit varnish, gum and sludge on the enginesurfaces, such as the cylinder walls, pistons and rings, andial'sotoinduce corrosionof bearing materials thereby causing failure of theengine. These'problemshave become increasingly serious because ofthetrend toward higher efficiency or higher power output per unit weight ofengine, which results in. conditions tending to accelerate thedeteriorating in- I 3 fluences on the mineral oil lubricant. Theformalubricating oils. The presence of gums, varnishes andsludges isdetrimental for" many 'reasons. These substances tendto increase ringsticking and ac'celerate the formation of further deposits on pistonsurfaces and in fixed parts of the com- The' sludges formed in thecrankcase of the engine increase the rate of cor- "rosion of bearingsurfaces,- especially of bearing alloys of the types now in use.

. In steam turbines, the corrosion'problem isparhearing corrosion,rustingmay also be encoun- I It is "an-:object'of'this invention,there-fore, to

prepare an improvement agent which willobvlate It is a. further objectof this invention to provide improved mineral oil lubricantvcompositions It is also an object of this invention to provide mineraloil lubricant compositions which have excellent pressure-carrying.properties.

In our 'copending application Serial No. 718,902, -'-filed' December27', 1946, there is disclosed and ,claimed an addition agent for mineraloil lubric'ants. which confers excellent antioxidant, corrosioninhibiting' and pressure-carrying properties on mineral oil lubricants.Such improvement agent is prepared by heatingan essentially 1.;parafiinic base lubricating oil with aluminum pchloride, removingaluminum chloride from the r'eaction product and reacting said productwith phosphorus pentasulfide at an elevated temperatime to incorporatephosphorus and sulfur therein.

is prepared by heating an essentially parafilnic chloride treatment ofthe lubricating oil as disclosed in our application Serial No. 718,902may beomitted. It is also shown in our latter filed plication that whenthe prior aluminum chlo- V ride treatment of the parafiinic baselubricating oil is combined with reaction of the aluminum chloridetreated product with phosphorus. penta- Fv sulfide in the presence of asurface active silicafcontaining catalyst, lighter colored products areobtained.

The objects of thepresent invention are accomplished. by providingimprovement agents for mineraloil lubricants by reacting anessentiallypar- "a'flinic base lubricating oil or the aluminum chloridetreated product thereof with phosphorus pentasu'lfide through the use ofany of the meths disclosed, in our copending applications Serial s.71.8,902and 736,618 and then reacting-the r sulting product with anester having the formula:

vhereinla and R1 represent aliphatic hydrocari radicals, atleastonegof'said radicals con- 1 taming olefinicunsaturation, and thesui n,ofthe 3 carbon atoms of both R and R1 being not less than 16. Suchimprovement agents, as well as the mineral oil lubricant compositionscontaining them, are believed to be novel and are considered parts ofour invention.

The present invention may be regarded as an improvement over theinventions disclosed in our above-identified copending applications.While the addition agents disclosed therein confer excellentantioxidant, corrosion-inhibiting and pressure-carrying properties onmineral oil lubricants, they sometimes fail topass the well known CopperStrip Test (Method 530.31, Federal Specification VV-L-79lc, May 12,1945, page 259) thus indicating the presence of elementary sulfur or theso-called corrosive sulfur. While we do not wish to be bound by anytheory as to the exact nature of our phosphorus pentasulfide reactionproducts, it is our present belief that either elementary sulfur rincompletely bound sulfur or both are formed in the reaction. Inaccordance with the present invention, such elementary or incompletelybound sulfur is neutralized by combination with the unsaturated esteradded to the phosphorus pentasulfide reaction product. In addition, theresulting products have enhanced pressure-carrying properties.

It is still necessary for the purposes of the present invention toemploy an essentially parafiinic base lubricating oil as the initialmaterial, be-

. cause other hydrocarbon materials produce a black, sludge-like,difiicultly soluble product regardless of whether the prior aluminumchloride treatment or reaction in the presence of a surface activesilica-containing solid catalyst are employed. The reasons for theadvantageous effects of the prior aluminum chloride treatment or of thesurface active silica-containing solid catalyst on the reaction when anessentially parafiinic base lubricating oil is employed are not fullyunderstood." However, the use of at least one of these methods isessential for the practice of our invention since, if the prior aluminumchloride treatment or the use of a surface active silicacontainingcatalyst is omitted, the advantageous results of our invention are notobtained. In order to obtain the results of our invention, therefore,it'is necessary (1) to employ an essentially paraflinic base lubricatingoil, and (2) to conduct the reaction of the oil with phosphoruspentasulfide only afteraluminum chloride has been reacted with the oiland/or the reaction with'phosphorus pentasulfide is conducted in thepresence of a surface active silica-containing solid catalyst. Theessentially paraflinio base lubricating oil used as a starting materialin accordance with our invention may be derived from any paraffiniccrude, such as Pennsylvania, Mid-Continent, or other paraffinic basecrudes. The lubricating oil is manufactured from such crudes inaccordance with conventional methods and may be refined in accordancewith methods known in the art. If it is desired to treat the essentiallyparaflinic base lubricating oil with aluminum chloride, such treatmentis accomplished as described in our copending application, Serial No.718,902. Brief- 1y, such treatment comprises heating the essentiallyparafiinic base lubricating oil with from 1' to per cent by weight ofanhydrous aluminum chloride at a temperature of from 150 to 300 F. whilethe mixture is vigorously agitated. The time of treatment may vary inaccordance with 4 temperatures. In general, the treatment will becompleted after four or five hours. After the treatment is completed,agitation is stopped and the sludge containingmost of the aluminumchloride settles out from the main body of the oil and is drawn off. Thesupernatant body of the treated oil may contain further quantities ofaluminum chloride finely dispersed therethrough, and in order to insurethe removal of all aluminum chloride from the treated oil, agitatingwith an adsorbent clay followed by filtration may be employed. At thehigher temperatures of treatment with aluminum chloride some conversionof the parafiinic base oil to lower boiling products may take place.Although such conversion is slight, the product may be topped ifdesired, that is, distilled to remove the lower boiling productsoverhead and to recover as a residue the bulk of the aluminum chloridetreated oil having a minimum initial boiling point in the range 490 to530 F. The essentially parafiinic base lubricating oil treated withaluminum chloride as disclosed hereinabove may then be reacted withphosphorus pentasulfide. This may be accomplished either by reactingwith phosphorus pentasulfide per se, as disclosed in our CODBIldlllgapplication Serial No. 718,902, or in the presence of a surface activesilica-containing solid catalyst as disclosed in .our copendingapplication, Serial No. 736,618.

If it is desired to react the aluminum chloride treated oil withphosphorus pentasulfide per se, this reaction is accomplished by addingfrom 2 to 20 per cent by weight of P285, preferably 5 to 10 percent, andheating with agitation at a minimum reaction temperature of 450 F. and amaximum reaction temperature below the temperature where cracking of theoil begins. Hydrogen sulfide is evolved and when the evolution ofhydrogen sulfide has nearly ceased, the temperature of the reactionmixture may be increased within the maximum temperature disclosed above,say to about 500 F. for the completion of the reaction.

If desired, the aluminum chloride treated parafiinic base lubricatingoil may be reacted with phosphorus pentasulfide in the presence of asurface active silica-containing catalyst; or, the prior aluminumchloride treatment may be omitted and the essentially paraffinic baselubricating oil may be reacted with phosphorus'pentasulfide in thepresence of a surface active silicacontaining solid catalyst. Thereaction of the essentially paraifinic'base lubricating oil, whether ornot pretreated with aluminum chloride, with phosphorus pentasulfide inthe presence of a surface active silica-containing solid catalyst isaccomplished by adding'2 to 20 per cent by weight of PzSs, preferablyfrom 5 to 10 per cent, to the essentially parafiinic base lubricatingoil and heating with agitation at a temperature in the range from 300 F.to a maximum temperature below the temperature where cracking of theoil, that is, 'pyrolytic decomposition of the oil, begins.

Generally the minimum cracking temperature of the oil varies between 490to 530 F., depending upon the particular oil used. The surface activesilica-containing solid catalyst is employed in the amount of aluminumchloride used and the};

temperature of treatment, longer times being rc quired with lessaluminum chloride and lower amounts of from 2 to 25 per cent by Weightof the oil charged and preferably in an amount of 10 per cent by weight.Larger amounts than 10 per cent are ordinarily not necessary, but largeramounts will produce a product having a lighter color. During the courseof the reaction hydrogen sulfide is evolved and the phosphorus andsulfur become incorporated in the oil. When cracking catalyst and thelike. Thus, activated clays, that is, natural clays such as bentonite,smectite, floridin, fullers earth and the like which have been treatedwith acid, such as are.

described in U. S. Patent No. 1,898,165, for example, may beadvantageously employed. Synthetic silica-alumina catalysts of the typeused for the cracking of hydrocarbon oils, examples of which aredescribed in U. S. Patent No. 2,078,945 and U. S. Patent No. 2,283,173,may also be employed. Activated silica gel is also suitable. Asmay beseen, the term surface active silica-containing solid catalyst comprisesa wide variety of materials, the predominant characteristic of which isthe presence of silica in a surface active, that is, activated form.

After reaction of the essentially paraffinic base lubricating oil withthe phosphorus pentasulfide as disclosed hereinabove, the resultingreaction products are reacted, in accordance with the present invention,with an ester having the formula:

wherein R and R1. represent aliphatic hydrocarbon radicals, at least oneof said radicals containing olefinic unsaturation, and the sum of thecarbon atoms of both R and R1 being not less than 16. The reaction withthe ester takes place at a temperature in the range 300 to 400 F.,preferably about 350 F. The ester is ordinarily added in proportionsranging from 1.0 to per cent byweight of the reaction mixture,sufiicient to combine with free or corrosive sulfur in the -'phosphoruspentasulfide reaction product. When reacted under these conditions, webelieve that theester is linked te the phosphorus pentasulfide reactionproduct through a sulfur atom, and any free sulfur will also react withthe ester.

Among the esters encompassed by the present invention and having theformula:

as defined hereinabove, there are included the following types:

(1)i Those esters in Which both R and R1 have v olefinic unsaturation.These include such esters as allyl oleate, decylene oleate, dodecylene'oleate,

pentadecylene oleate, oleyl oleate, and particularly sperm oil whichprovides an excellent source of this type of ester.

(2) These esters in which R has olefinic unsaturation, but R1 issaturated. These include methyl' oleate, isopropyl oleate, hexyl'oleate,

lauryl'oleate, cetyl oleate and the like. In lieu of esters of oleicacid, esters of other olcfinic mono-carboxylic fatty acids may beemployed,

such as esters of decenoic, undecenoic, linoleic and linolenic acids.

(3 These esters in which R is saturated,,but Rrhas olefinicunsaturation. These include allyl ,nalmitate', ,decylene, laurate,dodecylene caprylate and oleyl butyrate.

In. selecting any ester of the above: types, it should be borne in mindthat the; sum. of the carbon. atoms of. R and Rrmust benot: lessthan16'.

The. following examples illustrate the, preparation ofour newimprovement agents.

Example I Fifty-one parts by" weight of an essentially paraflinic baselubricating oil (S.A.E. 30) which had been treated with aluminumchloride in accordance with our copending application Serial No. 718,902were placed in a reaction vessel together with 5.6 partsby weight ofphosphorus pentasuliide. The mixture was then agitated and heated to 450F. for a period of 2 hours. The temperature was then gradually raised to525 F. over a period of 4 hours and maintained at that point for 2hours. The mixture was then cooled to 350 F. and 5.1- parts by weight ofsperm oil were added. The mixture was held at this temperature for 4hours and then cooled and diluted with anequal weight of a lightlubricating oil, thereby forming a concentrate of the improvementagent.The product had the following properties:

Gravity, API 24.0

Viscosity, SUV, F 520 Sulfur, per cent 1.94

Phosphorus, per cent 1.68

Example II An essentially parafiinic base lubricating oil (S.A.E. 50)was pretreated with aluminum chloride as herein disclosed and reactedwith 10 per cent by Weight of phosphorus pentasulfide at 500 Aftercompletion of the reaction, 10 per cent by weight on the reactionmixture of sperm oil was added and the mixture agitated for 6 hours at400 F. The product had the following properties Gravity, API 23.4Viscosity, SUV, 100 F 1692 Sulfur, per cent 4.5 Phosphorus, per cent 1.6Neutralization No 0.04

Example I II Five thousand four hundred parts byweight of an SAE 30grade essentially paraffinic base lubricating oil were reacted with 600parts by weight of phosphorus pentasulfide in the presence of 600 partsby weight of an activated clay catalyst at a temperature in the range480 to 500 F. The reaction was completed after 6 hours. The mixture wasthen cooled to 350 F. and 600 parts by weight of sperm oil were added.

The mixture was held at 350 F. for 2 hours and then filtered. Theproduct had the following f properties:

Gravity, API 22.6 Viscosity, SUV,210 F 78.7 Color, NPA 6.5 "Sulfur, percent 3.12 Phosphorus, per cent 2.33 Neutralization No 13.9

The reaction products obtained in accordance with the precedingvexamplesare excellent imprcvernent agents for mineral oil lubricantcompositions. "They are light-colored and readily soluble in all typesof mineral oils, that is paraffinic, naphthenic or mixed base mineraloils and,

as a matter of fact, can be blended with mineral oils in proportions ashigh as 50 per cent by weight or higher. This excellent solubility ofour new improvement agents enables the preparation of concentratedsolutions, which may then be diluted down to the proportion desired inthe final mineral oil lubricant composition. As stated, our newimprovement agents confer excellent pressure-carrying, anti-oxidant andcorrosion-inhibiting properties on the mineral lubricating oils withwhich they are incorporated. For these purposes, our new improvementagents are generally added to mineral oils in minor amounts, say from0.1 to 20 per cent by weight of mineral oil, sufficient to confer improved pressure-carrying, anti-oxidant and corrosion-inhibitingproperties on the mineral lubricating oils with which they areincorporated. When our new improvement agents are to be used for theiranti-oxidant and corrosion-inhibiting effects, small proportions as lowas 0.1 per cent by weight are suflicient to effect the improvement. Whenextreme pressure properties are to be conferred on a lubricating oil,higher proportions, as high as 20 per cent may conveniently be used.Lubricating oils containing our new improvement agents successfully passthe Copper Strip Test.

The following examples illustrate the use of our new improvement agentsto obtain improved mineral oil lubricant compositions.

properties of the improved lubricant and the base lubricant follows:

Base Improved Lubricant Lubricant Gravity: API- 28.2 28. 3 Viscosity,SUV:

210 F 67. 5 67.8 Viscosity Index. 101 102 Color, NPA 4. 5 4. 5 Sulfur:Per Cent 0.18 0.19 Phosphorus: Per Cent 0.03 Neutralization No nil 0.00Oxidation and Bearing Corrosion Test, Method 257, Gulf:

Duration of Test: Hrs 48 48 Oil Bath Temperature: I! 347 347 Air Rate:cc./Hr 2, 000 2, 000

Quantity of Oil' 0 300 300 Bearing Type. Gd-Ag Ou-Pb Dd-Ag Cu-Pb Wt.Change: Grains. 0. 0989 0. 1488 -0.0003 +0. 0035 Wt. Change: Per Cent-0. 51 0. 74 0.0l 0 02 Copper Strip Test Passes Passes Example VI Inorder to determine the improvement in pressure carrying propertiesobtained by using the addition agent of the present invention, additivesprepared in accordance with the disclosures of Serial No. 718,902,Serial No. 736,618 and in accordance with the present invention wereblended in a motor oil, and the lubricants were subjected to the Wellknown Falex Wear Test. In each instance, 15 parts by Weight of theaddition agent were added to 85 parts by weight of a highly refinedmotor oil. The uncompounded oil is included for purposes of comparison.

Example IV An improved motor oil was prepared by blending 0.3 per centby weight of the additive of Example II-with 99.7 per cent by Weight ofa highly refined motor oil. A comparison of the properties of theimproved lubricant and the base lubricant follows:

Unimproved Improved Lubricant Lubricant Gravity: API 29.2 29. 2Viscosity, SUV 100 F. 524 526 Color, NPA 1. 75 1. 75 Oxidation andBearing Corrosion Test, Method 257, Gulf:

Duration of Test: Hrs. 48 48 Oil Bath Temperature: F 347 347 Air Rate:coJHr 2,000 2, 000 Quantity of Oil: cc 300 300 Bearing Type CdAg Cu-PbCd-Ag Cu-Pb Wt. Change: Grams 0. 500 0. 250 0.06 0.157 Wt. Change: lerCeuL... -O. 25 0.06 0. 01 0.04 Copper Strip Test Passes Passes Example Vpara fiinic base motor oil; A comparison of the V The Oxidation andBearing Corrosion Test, Method 257 Gulf referred to in the foregoingexamples is conducted as follows: An alloy bearing shell of certaincommonly used standard dimensions is submerged in 300 cc. of the oil oroil composition to be tested in a 400 cc. Pyrex beaker and heated in athermostatic oil bath to 370 F. Air is then bubbled through the oil incontact with the bearing shell at a rate of 2000 cc. per hour. At theend of 48 hours the loss of weight and condition of the bearing shellare determined, the bearing shell being Washed free of oil and driedbefore weighing. When determining the effectiveness of variousimprovement agents, the usual procedure is to run a blank testsimultaneously with the oil composition being tested, employing for thatpurpose a sample of the untreated oil. In this test it is advantageousto employ commercial bearing shells. These shells comprise a suitablemetal backing faced with the alloy bearing metal. In this way the actualbearlng face is subjected to severe deterioration conditions. Bycomparison of the results of such tests with actual service tests, Wehave found them to be in substantial agreement as to suitability ofparticular lubricants.

As shown in the above examples, the addition of our new improvementagents to mineral oil lubricant compositions confers excellentpressure-carrying, anti-oxidant and corrosion-inhibiting properties. Atthe same time the compositions so obtained are stable in storage and useand have a color which is substantially unaffected by the addition ofthe improvement agent. The lubricants obtained pass the Copper StripTest and show enhanced pressure-carrying properties over the lubricantsof our copending applications.

While we have shown in the examples the preparation of compounded,lubricating oils, our invention is not limited theretobut comprises allmineral oil lubricant compositions containing our newimprovementagentsfs'uch as greases and the like. Furthermore,conventional addition agents such as viscosity index improvers, pourpointgdepressants and the like may be added withoutdeparting from thespirit of the invention.

We claim:

1. The process of preparing an improvement agent for mineral oillubricants which comprises heating an essentially paraffinic baselubricating oil with anhydrous aluminum chloride at a temperature offrom 150 to 300 F., removing aluminum chloride from the reactionproduct, reacting said product with phosphorus pentasulfide at atemperature of from 450 F. to a maximum temperature below the minimumcracking temperature of said product to incorporate phosphorus andsulfur therein, and then further reacting the resulting product at atemperature of from 300 to 400 F. with an ester having the formula:

wherein R and R1 represent aliphatic hydrocarbon radicals, at least oneof said radicals containing olefinic unsaturation, and the sum of thecarbon atoms of both R and R1, being not less than 16.

2. The process of claim 1, wherein the aluminum chloride is employed inan amount of from 1 to 20 per cent by Weight, the phosphoruspentasulfide is employed in an amount of from 2 to 20 per cent byweight, and the ester is employed in an amount of from 1 to per cent byweight, suificient to combine with free or corrosive sulfur in thephosphorus pentasulfide reaction prodnot.

3. The process of claim 2, wherein the ester is sperm oil.

4. The process of claim 2, wherein the product is dissolved in a minerallubricating oil.

5. The process of preparing an improvement agent for mineral oillubricants which comprises heating an essentially parafiinic baselubricating oil with phosphorus pentasulfide in the presence of asurface active silica-containing solid catalyst at a temperature of from300 F. to a maximum temperature below the minimum cracking temperatureof said lubricating oil to incorporate phosphorus and sulfur therein,and then further reacting the resulting product at a temperature of from300 to 400 F. with an ester having .the formula: 1

R- OR1 wherein R and R1 represent aliphatic hydrocarbon radicals, atleast one of said radicals containing olefinic unsaturation, the sum ofthe carbon atoms of both R and R1 being not less than 16, and recoveringthe reaction product.

6. The process of claim 5, wherein the phoscombine with free orcorrosive sulfur in the phosphorus pentasulfide reaction product.

7. The process of claim 6, wherein the ester is sperm'oil.

8. The process of preparing an improvement agent for mineral oillubricants which comprises heating-an essentially paraflinic baselubricating oil with from'l to per cent by weight of anhydrous aluminumchloride at a temperature of from 150 to 300 F., removing aluminumchloridefrom the reaction product, heating said product with from 2 to20 per cent by weight of phosphorus pentasulfide in the presence of from2 to 25 per cent by weight of a surface active silica-containing solidcatalyst at a temperature of from 300 F. to a maximum temperature belowthe minimum crackin temperature of the aluminum chloride treated oil toincorporate phosphorus and sulfur therein, and then further reacting theresulting product at a temperature of from 300 to 400 F. with an esterhaving the formula:

wherein R and R1 represent aliphatic hydrocarbon radicals, at least oneof said radicals containing olefinic unsaturation, the sum of the carbonatoms of both R and R1 being not less than 16, and recovering thereaction product.

9. The process of claim 8, wherein the ester is sperm oil and isemployed in an amount of from 1 to 10 per cent by weight, suflicient tocombine with free or corrosive sulfur in the phosphorus pentasulfidereaction product.

10. The product obtained by the process claim 1.

11. The claim 2.

12. The claim 4.

13. The product obtained by the claim 5.

14. The claim 8.

15. A lubricant composition comprising a major amount of a minerallubricating oil and a minor amount, sufiicient to confer improvedbearing corrosion-inhibiting properties on the composition of theproduct obtained by the process of claim 1.

16. A lubricant composition comprising a major amount of a minerallubricating oil and a minor amount, from 0.1 to 20 per cent by weight,of the product obtained by the process of claim 2.

17. A lubricant composition comprising a major amount of a minerallubricating oil and a minor amount, sufficient to confer improvedbearing corrosion-inhibiting properties on the composition, of theproduct obtained by the process of claim 5.

18. A lubricant composition comprising a major amount of a minerallubricating oil and a minor amount, from 0.1 to 20 per cent by weight,of the product obtained by the process of claim 6.

19. A lubricant composition comprising a major amount of a minerallubricating oil and a minor amount, suflicient to confer improvedproduct obtained by the process of product obtained by the process ofprocess of product obtained by the process of bearingcorrosion-inhibiting properties on the composition, of the productobtained by the process of claim 8.

20. The product obtained by. the process of claim 3.

21. The product obtained by the process of claim 7.

22. The product obtained by the process of claim 9.

23. A lubricant composition comprising a major amount of a minerallubricating oil and a minor amount, from 0.1 to 20 per cent by weight,of the product obtained by the process of claim 3.

24. A lubricant composition comprising a major amount of a minerallubricating oil and a minor amount, from 0.1 to 20 per cent by weight,of the product obtained by the process of claim 'I.

a 25. A lubricant composition comprising a ma jor amount of a minerallubricating oil and a minor amount, from 0.1 to 20 per cent by weight,of the product obtained by the process of claim 9.

HERSCHEL G. SMITH. TROY L. CANTRELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

, UNITED STATES PATENTS Number

16. A LUBRICANT COMPOSITION COMPRISING A MAJOR AMOUNT OF A MINERALLUBRICATING OIL AND A MINOR AMOUNT, FROM 0.1 TO 20 PER CENT BY WEIGHT,OF THE PRODUCT OBTAINED BY THE PROCESS OF CLAIM 2.